Fine-needle aspiration biopsy findings suspicious for papillary thyroid carcinoma: a review of cytopathological criteria.

OBJECTIVES/HYPOTHESIS: The objective was to evaluate the usefulness of standard suspect cytological features on fine-needle aspiration biopsy (FNAB) in predicting papillary thyroid carcinoma.

STUDY DESIGN

Retrospective chart review of consecutive fine-needle biopsies of the thyroid.

METHODS

The study was a retrospective review of consecutive patients presenting with a diagnosis of suspected (group 1) or positive papillary thyroid carcinoma (group 2). The frequency of standard cytological features (i.e., papillary architecture, multinucleated giant cell, nuclear pseudo-inclusions, nuclear grooves, micronucleoli, powdery chromatin, and psammoma bodies) were recorded for each group. These were compared using chi test. Sensitivity and specificity for both individual and a combination of features were calculated for patients in group 1.

RESULTS

One hundred eight patients were eligible for the study (group 1, n = 57; group 2, n = 51). Fifty-one patients (89%) in group 1 and all patients in group 2 had a histopathological diagnosis of papillary thyroid carcinoma. Respectively, the most frequent features present on fine-needle aspiration biopsy in group 1 versus group 2 were nuclear grooves (79% vs. 88%), micronucleoli (74% vs. 86%), pseudo-inclusions (58% vs. 88%), and powdery chromatin (47% vs. 59%); P values for these features were P > .05, P > .05, P < .05, and P > .05, respectively. In group 1, the sensitivities of nuclear grooves and micronucleoli were 80% and 71%, respectively. The presence of psammoma bodies was associated with a specificity of 100%. A combination of nuclear grooves, micronucleoli, pseudo-inclusions, powdery chromatin, and multinucleated giant cells was 100% specific in detecting papillary thyroid carcinoma.

CONCLUSION

In choosing the most appropriate management of a finding suspect for papillary thyroid carcinoma on fine-needle aspiration biopsy, the surgeon must be aware of the diagnostic importance of certain cytopathological features. The presence of a combination of these factors may allow a more confident surgical approach.